1. Field of the Invention
The present invention relates to wheeled carriers such as surgical tables, and, in particular, to an apparatus for supporting a wheeled carrier in a fixed location.
1. Description of the Invention Background
In various environments, it has proven necessary to support a wheeled carrier in a fixed location. For example, in connection with surgical tables it is necessary to allow a surgical table to be wheeled from a surgical patient preparation station to a surgical suite while supporting a surgical patient. However, while in the surgical suite, the surgical table must be maintained in a fixed location to allow the necessary surgery to be performed. Alternatively, if a wheeled surgical table is intended for use while supporting a patient within an image amplification apparatus, the table must be capable of being wheeled into position and locked in a fixed location relative to the image amplification apparatus.
Previously, wheeled tables were provided with a mechanical floor locking system. In such tables, casters were provided on the base of a surgical table. In order to fix such a table in a specific location, legs provided adjacent to each caster were lowered from the table base to support the table on the legs rather than on the casters. In order to deploy the supporting legs, a manually operated foot pedal was provided on the table base. The foot pedal was connected by an extended link to a cam member. The cam member was operatively connected to extended pivoted levers. In addition, the remote ends of the lever were pivotally connected to the supporting legs.
In the operation of such an apparatus, the activation of the foot pedal caused the cam member to be rotated. Such rotation caused the cam member to displace the inboard ends of the levers upwardly. The movement of the inboard ends of the levers caused the outboard ends of the levers to be lowered. This action caused the respective supporting legs to be lowered. The lowering of the legs allowed the table to be supported thereon in a fixed location rather than on the casters.
Applicants have discovered various problems with the prior mechanical cam/lever arrangement. First, it will be appreciated that the table weight to be lifted by the legs was significant; many such tables may weigh in excess of 800 pounds in addition to the weight of the patient. As such, the force required to lift the table by means of the legs in a single movement has proven excessive for hospital personnel. Further, the force required to raise the table yet further preliminary to the lowering of the table may also be unreasonably high. As such, means for raising a surgical table onto supporting legs which requires, at most, only a reasonable manual force is needed by the industry.
The functional requirements of such tables pose serious design problems which must be overcome in designing an alternative floor lock system. For example, the frequent use of such tables in connection with image amplification equipment requires that the means for deploying the supporting legs be compact in configuration. Meanwhile, as the tables must be completely portable, such as being capable of crossing elevator thresholds, the floor lock system must be retractable to a considerable degree. Accordingly, significant design constraints are imposed on surgical table floor lock systems.
The subject invention is directed toward an improved surgical table floor lock apparatus which overcomes, among others, the above-discussed problems and provides a table support system which is effective to support the table in a fixed location while requiring, at most, a minimum amount of manual exertion.